Methods of reducing kinetic friction are known in the prior art. According to these methods, rolling parts are placed between moving closed surfaces. The rolling parts can be fixed or free. These types of methods are implemented in translational or rotational engagements.
The present patent mainly relates to a rotational engagement, but can also be extended to a translational type of engagement.
Roller bearings, which substitute kinetic friction with static one are widely used in this technology, improving performance of devices and reducing power losses.
The roller bearings consist of concentric inner and outer races with tracks on their surfaces. The space between the races is filled with rolling parts. The rolling parts roll on the tracks of the surfaces minimizing the kinetic friction.
The roller bearing known in the prior art contains one orbital row of rolling parts and a separator that provides spatial separation between the rolling parts and determines the relative distance between them. The motion of the roller bearing is effected by not only contacts of the rolling parts with tracks, but also by their slipping contacts with the separator.
There are number of attempts known in the prior art to avoid the use of a separator in order to improve the functionality of the system of this type. This can be done by reducing or removing the slippage of the system's parts as well as distributing the radial and frictional loads over all of the rolling parts and contact surfaces of the race tracks.
U.S. Pat. No. 4,208,077 discloses a bearing with a second orbital row of rollers which encircles the first row in such a way that each roller of the outer row is in contact with the outer race track and two rollers of the inner row, and each roller of the inner row is in contact with the inner race track and two rollers of the outer row. One of the rollers is concave and consists of two conical parts. These two conical parts are connected by an adjustable screw for varying their axial mutual position. The said composite roller is inserted to the roller bearing at the last stage of its assemblage. The change in the relative distance between the two parts of the composite roller should enable the precise fitting of races, balls and parts to maintain slack-free engagement.
U.S. Pat. No. 4,326,759 discloses a bearing with a third row of rollers positioned between the first and the second row. Each roller of the second row is in contact with two rollers of adjacent inner and outer rows. Constant engagement should be achieved due to the precision of the bearing parts, which provides the retention of the engagement and lengths of orbital rows ensuring concentricity of the races.
U.S. Pat. No. 4,053,191 presents a method for producing rolling-contact-only bearings with rotating elements and rings. The rings acting as springs should ensure continuous separation between all rotating elements, thereby carrying the entire bearing load and permitting radial deflection under load to avoid slippage of the elements. The retention of the engagement should provide concentricity of the races.
Methods for using two tracks and several rows of rollers between them as a frictional reduction gear are also known in the prior art.
One of these methods is disclosed in U.S. Pat. No. 1,737,695. The author suggests the use of inner and outer races as well as several rows of rolling parts in the method described above with two modifications:                for the adjustment of mutual retention between the parts a pressure roller is mounted between two adjacent rollers. The pressure roller is in contact with other two rollers that belong to a row and it is not connected to the races. The radial displacement of the pressure roller results in a change of mutual position of the two friction rollers and consequently effects on orbit lengths of all rows and retention of the engagement.        to ensure the concentricity the races, they are engaged by two additional bearings.        